1. Field of the Invention
This invention relates generally to a method and apparatus for electrically dispersing ionized fluids as an aerosol for improving air quality and more specifically, to a method and apparatus for generating a negative ion aerosol comprising ozone-free negative ions.
2. Prior Art
U.S. Pat. No. 3,085,749 to Schweitzer et al is directed to an electrostatic spray head and includes a head coupled to a shaft through a chuck. High electrical potential for the head is supplied from a source of high voltage through a slip-ring. A fluid such as paint is supplied to the head from a nozzle. The object is mounted in front of the head and is coupled to ground. This reference does not take place the electrode within the fluid.
U.S. Pat. No. 3,296,491 to Brown is directed to a system for producing ions and electrically charged aerosols. The structure includes an elongated electrode which is coupled to the edge of a vane electrode by insulators. The electrodes are maintained at different electrical potentials by the power supply.
U.S. Pat. No. 2,655,107 to Godbold is directed to an electromagnetic fluid pump. In order to produce a flow force on the liquid in a duct, a pair of contacts are provided on the duct. The contacts may penetrate the duct if the duct is of a dielectric material.
U.S. Pat. No. 4,431,137 to Prewett et al is directed to systems for spraying liquid metals. An electric field to disrupt the film of liquid metal forming over an emitting point is applied to the source by an extraction electrode and a terminal.
U.S. Pat. No. 4,264,641 to Mahoney et al is directed to an apparatus for electrohydrodynamic spraying of molten metal (conductive) materials to produce thin film coatings.
The prior art reveals that it is known that a liquid can be dispersed with electrification and that one such dispersal mechanism can consist of a capillary filled with distilled water which forms a fountain with positively charged electrification. The prior art patents show electrodes in close proximity to achieve high electric fields. However, the prior art fails to show the manner required to create a negative ion generator using water as a medium. This is because two essential ingredients of the present invention are missing. More specifically, there is no showing that water forms a dispersion from a negative electrode in the range of voltages suitable for safe ion generation. Secondly, there is no showing that placing a negative electrode in contact with the liquid going into a capillary causes a dispersion to form from the tip of the capillary with any water composition in the voltage and current range under 15,000 Volts and less than one milliAmp. For example, in the Brown patent, a complex apparatus is described having veins and grids in structures designed to form ions with electrohydrodynamic and electrokinetic forces. The liquids disclosed for use in the Brown patent are ionized by high voltage ultraviolet and nuclear sources and then propelled with shaped electrical fields into the atmosphere to produce the desired aerosol. This patent indicates that the operating range is between 10 and 70 kiloVolts using a fine tungsten or stainless steel wire as an electrode. No characteristics of the liquid are specified and the output charge in the atmosphere is not described. More specifically, for the level of voltages specified the generation of ozone may reach intolerable levels particularly at low humidity.
In an early patent, namely, U.S. Pat. No. 705,691 to Morton dated 1902, an electrically polarized atmosphere is produced by passing an electric current of high tension through the atmosphere. Two electrodes are shown by Morton and little description is made of the liquid properties except as mixtures for separation. Morton is clearly interested in separating components of a liquid mixture and not in optimally placing charges into the air. The only dispersive effect apart from separation is the apparent improvement in the evaporation of the more volatile components of the liquid. Furthermore, Morton specifically refers to the production of ozone which he relies upon to ozonize the material in the process of forming the separating. All cited examples of the prior art and specifically U.S. Pat. No. 705,691 assume that electrode contact with the liquid is all that is required. However, the applicant has discovered that merely contacting the liquid in the spraying of water does not produce a fountain, in fact, except for the invention disclosed herein, water cannot be sprayed without a system that is predominantly mechanical. All prior low voltage systems not used for precipitation of particles and other systems of high voltage designed for use outdoors use electrostatic fields to aid in the placement of droplets or in electrohydrodynamic propulsion in outer space.